This is a proposal for support of an international scientific meeting (ESPHI 99) which will be held in Washington, DC on May 11-15, 1999. The purpose of the meeting is to examine the most current information relating to maturational aspects of the developing immunologic and hematologic systems and its clinical application(s) to human disease. In general, disorders of the immunologic and hematologic systems have in common the dual dependency on genetic endowment and environmental exposure. Although considerable advances in our knowledge of the cellular and molecular events associated with fetal and neonatal development of these systems has been made in recent years, comparatively little is known how to apply and optimize this information to the prevention or treatment of a wide variety of hematologic and immunologically-mediated diseases. In recent years, for example, there has been an alarming increasing incidence of asthma and the the allergic diseases, which may be a function of both genetic (i.e., atopy) as well as environmental factors (i.e., pollution). Similarly, although great strides in our knowledge of stem cell development are reaching fruition in the application to correction of genetic, metabolic, immunologic and malignant disease and transplantation, there exists a dearth of knowledge of how to specifically, apply this knowledge to the patient. The important nutritional and immunologic effects of breast feeding are likewise gaining clinical recognition in the amelioration and prevention of allergic, hematologic and infectious diseases. Because of the importance of these rapidly emerging disciplines, we propose to organize and conduct an international congress to facilitate an exchange of the most current knowledge in these areas, and to assist the National Institute of Child Health and Human Development to identify and foster new areas of collaborative research. The congress will be organized in the following scientific sessions: 1) immunology, 2) coagulation, 3) erythropoiesis, 4) stem cells, 5) research in developing countries, 6) neonatology 7) bone marrow transplantation/gene therapy, 8) cell biology, 9) free papers. Approximately 17 senior participants from the US and Europe will be invited on the basis of their expertise and current scientific contributions. In addition, a major goal of the congress will focus on the support of young investigators who will be invited to present their work at a special young investigator poster symposium. An additional advantage in hosting the congress in Washington, DC is its proximity to NIH and other US institutions from which many of our speakers will be invited.